Safety device for heating and other apparatus



July 14, 1942.

SAFETY DEVICE FOR HEATI Filed Dec.

- Q j i @2 C. V. HILDEBRECHT us AND OTHER APPARATUS @afld? Patented July14, 1942 SAFETY DEVICE-FOR HEATING AND OTHER APPARATUS Charles V.Hildebrecht, Chicago, Ill., assignor to Milwaukee Gas Specialty Company,Milwaukee, Wis., a corporation of Wisconsin Application December 12,1938, Serial No. 245,076

19 Claims.

tion, Serial No. 239,799, filed November 10, 1938. r

I More particularly, the invention relates to safety devices of thegeneral character in which an electromagnet connected in circuit with athermocouple is adapted to beenergized by the thermo-electric currentset up by the thermocouple as long as the burner, to the heat of whichthe thermocouple is subjected, such as a pilot burner, is lighted, andwhen so energized, maintains a valve or other controlling member forcontrolling the supply of fuel or operative energy to the apparatus inopen or operating position; cessation of the holding action oftheelectromagnet, upon extinguishment of the burner or upon opening of thethermo-electric circuit, releasing the valve or controlling member formovement to closed or safety position shutting off the supply of fuel oroperative energy to the apparatus; One of the main objects of thepresent invention is to provide a tripping and resetting combinationgenerally such as disclosed in my above identified copending applicationand of a character not only automatically to maintain the supply of fuelto the burner as long as it is desired to supply heat therefrom andautomatically to shut off the fuel supply when heat from the bumer isnot desired and to set up the supply of fuel when heat from the burneris again desired, but,

further, automatically to shut oi? the supply of fuel to the pilotburner with the shutting off of the supply of fuel to the main burnerand to reestablish the supply of fuel to the pilot burner andautomatically ignite the same in the resetting operation whichreestablishes the supply of fuel to the main burner.

It is also an object of the present invention to prevent overheating inthe event of failure of the circuit other than the i thermo-electriccircuit, and, more particularly, to avoid failure to trip theelectromagnetlto release the valve or controlling member for movement toclosed or safety position when, for example, the other'circuit fails anda desired temperature is exceeded or other abnormal defective orinsuflicient functioning or non-functioning of the apparatus occursFurther objects and adv ntages of the invention will appear from thefollowing detailed de-'- scription, taken in connection with the, 'acoompanying drawing in which the single figure is a diagrammatic view,partly in sectiomoi' an'illustrative embodiment of the presentinvention.-

Referring to the drawing, the burner I0 is any suitable or preferredmain burner-by way of example, the main burner for a water heater or fora space or room heater, or it may be the main burner for certain typesof ovens or other heating apparatus, or any other burner.

A pipe, indicated diagrammatically at H, supplies gaseous or any othersuitable fuel to the burner ID. A valve body shown fragmentarily at I2is connected into the fuel supply pipe I I. The valve body I! has avalve opening or port I3. Disposed in juxtaposition to the burner I0 isa pilot burner M which maintains a pilot flame l5 for igniting the mainburner. The pilot burner i4 is supplied with fuel by a tube l6 which ispreferably connected through a port H with the valve opening l3 betweenthe valve seats l8 and I9 at opposite ends thereof.

A valve 20 is adapted to seat upon the seat I8 at the outer end of thevalve opening l3 to shut off the fuel supply to the main burner l0 andalso the fuel supply to the pilot burner Id. The valve 20 is connectedby a;valve'stem 22 to an armature 23, and a helical spring 24 surroundsthe valve stem with one end engaging the valve 20 and the other endengaging a fixed part 25 of the control device. The spring 2| isnormally under compression when the armature is in attracted position,but when the electromagnet, indicated generally at 28, is energized andthe armature 23 is held in attracted position thereby,

the spring 24 is prevented from moving the valve 20 to closed positionengaging the valve seat N and the pilot burner.

Upon cessation of the holding action of the electromagnet 28 as, forexample, upon extinguishment of the pilot flameat the pilot burner It orupon tripping of the electromagnet as will hereinafter appear, thearmature 23 and connected valve 20 are released, whereupon the valve -20is moved by the spring 24 into engagement with the valve seat It to shutoil! the supply of fuel to the main burner and also to the pilot burner.

The electromagnet 28 cpmprises a magnet frame 30 having energizing coilmeans. In the illustrated embodiment of the invention, the magnet frameIt is of generallyu shaped form, and the coil means 32 surrounds each ofthe legs of the magnet frame. It is to be understood that theelectromagnet may be of any other suitable or; preferred form; The coilmeans 32, instead of surrounding each of the legs or'tlie magnet frame,may surround only one leg, and a trip coil may be provided around theother leg as disclosed and for the purposes set forth in my copendingapplication Serial No. 239,799, filed November 10, 1938, and in thecopending application of John H. Thornbery and Theodore A. Wetzel,Serial No. 283,572, filed July 10, 1939. The coil means 32 is connectedin circuit with the a thermocouple 35 as will presently be described.

disclosed in Oscar J. Leins Patent No. 2,126,564,

granted August 9, 1938, or it may be in the form of any of thethermocouples or multiple thermocouple devices disclosed in thecopending application of Guido Wunsch and Josef Schuppert,

Serial No. 738,370, filed August 3, 1934, or of any other suitable orpreferred form.

One terminal of the coil means 32 is connected through a conductor 38 tothe internal thermocouple element of the thermocouple 35, and the otherterminal of the coil means 32 is connected by a conductor 46 in circuitwith a fixed contact 42. supported adjacent the contact 42 and insulated1 therefrom as indicated at 4'4. The contact 43 is connected in circuitwith the external metallic tubular thermocouple element of thethermocouple 35 by a conductor 45. The spring contact 43 is preferablytensioned normally to engage the contact 53 with the contact 42 at 46.

A second fixed contact 48, positioned in spaced relation with respect tothe contact 42, is connected, for example, through the Winding of anelectromagnet 49, a conductor 52, relay 53, and conductor 54, to theconductor 55 of a circuit 55, 56. The circuit comprising the conductors55, 56 is connected to a suitable source of current, for example througha transformer Eill to an alternating current circuit 58. The circuit 58may, for example, be an alternating current lighting circuit or anyother alternating current circuit supplied by a suitable source ,ofalternating current (not shown), although of course a direct currentresetting circuit, as well as other resetting arrangements, may beemployed within the scope of the broader aspects of the presentinvention.

A. thermally sensitive member or thermostat 60 is fixedly supported atone end at 62 and carries, at its opposite end, a contact 63 backed byan insulating piece 64, the contact 63 and insulating piece 64 beingmoved by the action of diflerent temperatures upon the thermostat 60.For example, upon a predetermined maximum temperature adjacent thethermostat, the insulating piece 64 engages the projecting end of thecontact spring 43 and separates the same from the contact 42 to open thethermo-electric circuit at 46. temperature adjacent the thermostat thecon tact 63 engages the contact 48.

The thermostat 60 shown in the drawing comprises a pair of strips formedof dissimilar metal and secured together, the strips having differentcoeflicients of expansion, and the thermostat has i a bimetal spiral orcoiled portion as shown. The

A spring contact 43 is fixedly.

Upon a predetermined minimumcircuit for conducting current from thecircuit 55, 56 to the contact 53. This may be varied so that the bimetalthermally sensitive element is removed from the electric circuit.Moreover, the thermostat maybe of any other suitable or preferred type,and I contemplate other devices such as a pressure responsive device ora humidity responsive device, or a device responsive to some otherconditions for actuating the contact 63 and insulating piece 64.

The reset means for resetting the armature 23 into attracted positionand the valve 29 to open position comprises a reset stem '60. Theresetting electromagnet 'H cooperates with the stem 10 for the purposeof actuating this stem inwardly to reset the device by engaging thevalve 20 and moving the valve to open position and the armature 23 toattracted position. In the embodiment of the invention illustrated inthe drawing, the reset electromagnet H has a magnet frame l2 with themagnet coil 73 surrounding the same. The stem 70 is preferably formed ofnon-ferrb magnetic material, and its outer end carries an armature 75formed of a suitable magnetic material. When the circuit through thecoil l3 is closed, the electromagnet H is energized and moves thearmature 15 to attracted position, this movement of the armatureactuating the reset stem inwardly to reset the device.

For the purpose of shutting ofi the supply of fuel to the main burnerduring the resetting operation, the reset stem 10 is'provided with avalve member E8 of the general character disclosed and claimed in myprior Patent No. 2,114,446, granted August 19, 1938. A stop 19 fixed onthe stem '50 .limits the outward movement of the reset stem, and acoiled spring 89, interposed between the stop 19 andthe valve 18 whichis loose on the stem, moves the valve 78 yieldingly to closed positionengaging the valve seat 89 by the movement of the stem 10 in theresetting operation. A coiled spring 82, interposed between the valve l8and a fixed part of the control device, .moves the valve 18 to openposition and the armature E5 to retracted position upon completion ofthe resetting operation. One terminal of the reset coil 13 is connectedby a conductor 84 to the conductor 55 of the circuit '55, 56, and theother terminal of the coil 13 is connected through a conductor 85 to aeon-' tact 86 in juxtaposition to the electromagnet 49. A leaf spring81, fixedly supported at 88 and connected at its fixedly supported endby a conductor 90 with the conductor 56 of the circuit 55, 56, carries acontact 9! which is adapted to engage the contact 86 for closing thecircuit through the coil 13 of the reset electromagnet whereby theresetting operation is secured. The leaf spring is tensioned to opencircuit position against a stop 89 as shown in the drawing. An arm maybe employed instead of the leaf spring 81, and this arm may .bepivotedat 88 and normally held inppen circuit position by a suitablespring. The contact 86 may be in the form of a leaf spring carrying acontact for cooperation with the contact 9 I; as shown.

The free end of the spring or arm 81 projects beyond the contact 9|, andthe electromagnet 49 is provided with an armature 94 pivoted, forexample, at 95. The armature 94, upon completion of the circuit throughthe electromagnet 49, is actuated to attracted position, and, by suchactuation, engages the. projecting end of the spring or arm 81 and movesthe contact 9| into engagement with. the contact 86 to close the resetcoil circuit 84, 05. A spring 00, connected to the armature 04 at oneend and fixedly anchored at the other end, returns the armature 04 toretracted position when the electromagnet 40 is deenergized.

For the purpose of automatically igniting and.

conductor I03 and conductor 05 to the contact 1 means at 85. k I

The relay at 53 is shown as of a form generally similar to thatdisclosed in the copending application of Clarence Wantz, Serial No.733,722, filed July 5, 1934. Any other relay or equivalent device iscontemplated within the scope of the present'invention.

The operation of the device is as follows:

When the pilot flame I5 is burning, the heat thereof upon the thermalJunction 30 of the thermocouple produces a thermo-electric currentin'the coil 32 and the connected thermoelectric circuit. The magnetframe 30 and armature 23 are preferably formed of an alloy of relativelylow magnetic reluctance'and, as a result, with the switch 42, 43 closedat 40, the relatively weak thermo-electric current produces a magneticforce of sufficient strength so that when the armature 23 is placed incontact with the pole ends of the magnet frame the magnetic attractionholds'the armature in attracted po-- sition with a force greater thanthe force exerted by the spring 24, thereby holding the valve 20 open,so long as the pilot flame is burning, and

the contacts 42, 43 closed at 45. Fuel then passes through the pipe IIto the main burner I0, and through the .pipe II, port I1 and tube I tothe pilot burner I4.

.If the pilot flame at I is extinguished, the

holding action of the electromagnet ceases to be sufficient to hold thearmature 23 in attracted position and the spring 24 moves the valve 20to closed position. The closing of the valve 20. "shuts off the supplyof fuel to themain burner I0 and also to the pilot burner I4.

On the other hand, with the pilot burner I4 ignited and the valve 20held open by the thermo-electric current developed by the pilot bum-'magnet ceases to be suflicient to hold the armature 23 and valve 20 inattracted position and the spring 24 moves the valve-to closed positionto shut off the supply of fuel to the main burner and to the pilotburner.

electromagnet. The armature I0 is attracted and actuates the reset stemI0 inwardly to reset the arma e 23 to attracted positidn and the valve20 to open position. If the piiot burner is lighted, the energization ofthe lectromagnet 20 thereby will retain the armature 2s m attractedposition and the valve 20 open.

To prevent the escape of unburned fuel from the .main burner during theresetting operation and until the supply of fuel is set up to the pilotburner and this burner has been ignited or reignited, the valve 10operates to shut off the supply of fuel to the main burner during theresetting operation. In the inward movement. of the stem 10 in theresetting operation, the valve 20 is opened and sets up a supply of fuelthroughthe valve opening I3, but the valve 10 immediately closes off thesupply of fuel to the main burner.

Fuel then passes out through the port I1 and tube I5 to the pilotburner. The pilot burner being extinguished so that the thermocouple isnot heated thereby, the relays 53 will be in the position with theigniter circuit closed at I20. The circuit from one side of the sparkgap igniter I00 is thereby completed through the conductors I02 and 54to one side of the circuit 55, 56, and from the other side of' thecircuit 55, 56 through the closed contacts 00, 0|, and conductors 85 andI03, to the other side of the spark gap igniter. As a result, sparkingoccurs across the spark gap igniter, and this ignites thefuel issuingfrom the pilot burner to form the pilot flame l5.

As soon as the pilot burner I5 is thus ignited it heats the junction 35of the thermocouple and, as a result, the relay 53 is, operated to openthe circuit at I20 by the thermo-electric current. I

The opening of the relay 53 thus opens the circuit for the igniter I00and also the circuit for the electromagnet 40., During the time theelectromagnet 40 is energized and until the pilot burner is ignited andhas heated the thermocouple, the switch 00, 01 is held closed at 8|,thereby maintaining energization of the reset coil 13 and holding thearmature 23 in attracted position and the valve-20 open as well as thevalve 18 closed,'until the thermocouple is heated by the pilot flame andthermo-electric current is set up to energizelthe the space or roomwhich is heated. Other con- Where the temperature to which thethe'nnocircuit for the electromagnet. 40, closes the conts 0|, 80. Thiscloses the circuit 84, 85 for the resetting coil I3 which energizes theresetting electromagnet 28 sumciently to hold the armature 23 attractedand the valve 20 in open position', whereupon the thermo-electriccurrent, by opening the relay I3 at I28 and deenergizing theelectromagnet 40, opens the reset circuit 04, at 0|. The reset stem isthereupon projected outwardly by the spring 82, opening the valve 18 toprovide a supply of fuel for the main burner, the valve 20 beingretained open by the thermoelectric current.

Where a thermally responsive control is provided at 00, the thermostatthereof may, as already pointed out, be of any suitable or, preferredform. Where the apparatus is employed in connection with a water'heater,the thermostat may be subject to the temperature of the water in thetank, and where the apparatus is employed in connection with a. space orroom heater, the thermostat may be subject to'the temperature of trolsat 00 will be subject to other conditions at which it is desired to tripand reset the device as herein described.

with the present invention, the valve .20 is tripped and resetautomatically upon the occurrence--- of predetermined conditions. Thefuel supply for the pilot burner is arranged to be shut on by the valve20 which shuts off the fuel supply By opening the thermo-electriccircuit at at at a predetermined maximum temperature, the electromagnet28 is tripped and the valve 2t closed at that time regardless of thecircuit 58. Overheating, therefore, cannot result, even upon failure ofthe line 58.

The spark gap igniter Hill is operated by the means 60 which operatesthe reset means, and, as a result, the fuel which issues from the pilotburner is ignited. The pilot burner, upon being. thus ignited, heats thethermocouple, which sets upon a thermo-electric current, therebyenergizing the electromagnet 28 to hold the valve 28 open, thethermo-electric current also opening the relay 53 at E28. The opening ofthe relay at H discontinues the operation of the igniter and deenergizesthe electromagnet 39 so that the reset circuit is opened. The reset stemis then actuated outwardly as previously set forth, and the valve 718moves to open position to set up the desired supply of fuel for-the mainburner.

. I do not intend to be limited to the precise details shown ordescribed.

I claim:-

I. Safety device for heating and other apparatus comprising, incombination, heat generating means, pilot means for said heat generatingmeans, means to control the supply of operative energy to said heatgenerating means and said pilot means, an igniter for said pilot means,a thermocouple subject to the heat of said pilot means, an electromagnetconnected in circuit with said thermocouple and adapted to cause saidcontrol means to supply operative energy to said heat generating meansand said pilot means while said pilot means is operative and to shut oilthe supply of operative energy to said heat generating means and to saidpilot means when said pilot means becomes inoperative, means forresetting said electromagnet and said control means to operativeposition to supply operative-energy to the apparatus and for renderingsaid igniter operative, and means controlled by said thermocouple forrendering said resetting means and said igniter inoperative when saidelectromagnet is operative to cause said control means to supplyoperative energy to said heat generating means and to said pilot means.I

2. Safety device for heating and other apparatus comprising,in'combination, heat generating means, pilot means for said heatgeneratingmeans, means to control the supply of operative energy to saidheat generating means and said pilot means, -an igniter for said pilotmeans, a thermocouple subject to the heat of said pilot means, anelectromagnet connected in circuit with said thermocouple and adapted tocause said control means to supply operative energy to said heatgenerating means and said pilot means while said pilot means isoperative and to shut off the supply of operative energy said controlmeans to operative position to sin aee oie ply operative energy to theapparatus and for rendering said i'gniter operative, means con-- trolledby said thermocouple for rendering said resetting means and said igniterinoperative when said electromagnet is operative to cause said cor; trolmeans to supply operative energy to saiz. heat generating means and tosaid pilot means, and means subjectto abnormal, defective, orinsufficient or non-functioning of the apparatus for tripping saidelectromagnet to shut off the supply of operative energy to said heatgenerating means and said pilot means.

3. Safety device for heating and other appa" ratus comprising, incombination, heat generating means, pilot means for said heat generatingmeans, means to control the supply of operative energy to saidheat-generating means and said pilot means, an igniter for said pilotmeans, a thermocouple subject to the heat of said pilot means, anelectromagnet connected in circuit with said thermocouple and adapted tocause said control means to supply operative energy to said heatgenerating means and said pilot means while said pilot means isoperative and to shut oil the supply of operative energy to said heatgenerating means and to said pilot means when said pilot means becomesinoperative, means for resetting said electromagnet and said controlmeans to operative position to supply operative energy to the apparatusand for rendering said igniter operative, means controlled by saidthermocouple for rendering said resetting means and said igniterinoperative when said electromagnet is operative to cause said controlmeans to supply operative energy to said heat generating means and tosaid pilot means, and means subject to abnormal, defective, orinsuflicient or nonfunctioning of the apparatus for tripping saidelectromagnet to shut oil the supply of operative energy to said heatgenerating means and said pilot means, said resetting means and saidigniter being controlled by another condition of the apparatus and bysaid thermocouple.

4. Safety device for heating and other apparatus comprising, incombination, heat generating means, pilot means for said heatgeneratingmeans, ,means to control the supply of operative energy to said heatgenerating means and saidpilot means. an igniter for said pilot "means,a thermocouple subject to the heat of said pilot means, an electromagnetconnected in circuit with said thermocouple and adapted to cause saidcontrol means to supply operative energy to said heat generating meansand said pilot means while said pilot means is operative and to shut offthe supply of operative energy to said heat generating means and to saidpilot means when said pilot means becomes inoperative, means forresetting said electromagnet and said control means to operativeposition to supply operative energy to the apparatus and for renderingsaid'igniter operative, means controlled by said thermocouple forrendering said resetting means and said igniter inoperative when saidelectromagnet is operative to cause said control means to supplyoperative energy to said heat generating means and to said pilot means,and means actuated to operative position by the resetting operation toshut off the supply of operative energy to the heat generating meansduring the resetting operation.

5. Safety device for heating and other apparatus comprising, incombination, means to control the supply of operative energy to theapparatus, heat generating means, pilot means for magnet inoperative.

said heat generating means, a thermocouple subject to the heat of saidpilot means, an electromagnet connected in circuit with saidthermocouple and adapted to cause said controlling means to supplyoperative energy to the apparatus while said pilot means is operativeand to shut oil the'supply of operative energy to the apparatus whensaid pilot means becomes inoperative, means subjectto a condition ofsaid ap-' paratus for opening the circuit including said thermocoupleand said electromagnet to shut oil. the supply of operative energyto theapparatus when the functioning of the apparatus is such as not torequire a supply of operative energy, means other than saidelectromagnet alone and subject to another condition of the apparatusfor' resetting said electromagnet and said controlling means tooperative position to maintain the supply of operative energy to theapparatus when the functioning of the apparatus is such as to require asupply of operative energy thereto, an igniter for said pilot means, andmeans controlled by the thermocouple for rendering said igniter and saidresetting means inoperative when the pilot flame is established and saidelectromagnet energized by the thermo-electric current set up by thethermocouple.

6. Safety device for heating and other apparatus comprising, incombination, means to control the supply of operative energy to theapparatus, heat generating means, pilot means for said heat generatingmeans, a thermocouple subject t the heat of said pilot means, anelectromagnet connected in circuit with said thermocouple and adapted tocause said controlling means to supply operative energy to the apparatuswhile said pilot means is operative and to shut off the supply ofoperative energy to the apparatus when said pilot means becomesinoperative, means other than said electromagnet alone for resettingsaid electromagnet and said controlling means to operative position tosupply op'erative energy to said heat generating means and said pilotmeans, an igniter for said pilot means, and thermally responsive meansfor opening the thermo-electric circuit including said electromagnet andsaid thermocouple at a predetermined maximum temperature and forrendering said re-" setting means and said igniter operative atapredetermined minimum temperature.

7. In a device of the character described, in combination, a burner, afuel supply pipe leading to said burner, a valve in said pipe, a supplypipe for a pilot light in juxtaposition to said burner, anelectromagnet, an armature for said electromagnet which, when attracted,maintains said valve in open position and, when retracted, compelsclosing of said valve, a thermocouple placed in position to be heated bysaid pilot light and connected incircuit with said electromagnet, a

second electromagnet connected in circuit with a source of current andadapted for resetting said armature to attracted position, an igniterfor said pilot light connected in circuit with said secondelectromagnet, and relay means controlled by the thermo-electric currentgenerated by the heat of the pilot'light on the thermocouple forrendering said igniter and said second electro- 8. In a thermoelectriccontrol apparatus for a burner, the combination with a burner, a fuelburner, an electromagnet, an armature for said electromagnet which, whenattracted, maintains said valve in open position, and when retractedfrees said valve for movement to closed position, and thermocoupleplaced in position to be heated by said pilot light and connected incircuit with said electromagnet so as to energize s'aid electromagnetsufliciently to hold said armature in attracted position and said valvein open position, said valve being incapable of being actuated toopen'position by the thermo-electric current generated by the heat ofthe pilot light on said thermocouple, of a second electromagnetconnected in circuit with a source of current and adapted for resettingsaid armature to attracted position and said valve to open position, andmeans for interrupting the circuit through said second electromagnetupon completion of the resetting operation.

9. Ina device of the character described, in combination, a burner, afuel supply pipe leading to said burner, a valve in said pipe, a supplypipe for apilot light in juxtaposition to said burner, an electromagnet,an armature for said electromagnet which, when attracted maintains saidvalve in open position and, when retracted,

compels closing of said valve, a thermocouple placed in position to beheated by said pilot light and connected in circuit with saidelectromagnet, a second electromagnet connected in circuit with a'source of current and adapted for resetting said armature to attractedposition, means subject to the heat supplied by said burner for closingthe circuit through said second electromagnet at a predeterminedtemperature, and means under the control of the thermoelectric currentgenerated by the heat of the pilot light on said thermocouple forinterrupting the circuit through said second electromagnet uponenergization of said first electromagnet.

10.- In a control device for heating and other apparatus, incombination; a main burner, a fuel supply pipe leading to said burner, avalve in said pipe, a fuel supply pipe for a pilot light injuxtaposition to said burner, an electromagnet, an armature for saidelectromagnet which, when attracted, maintains said valve in openposition and, when retracted, frees said valve for movement to closedposition, a thermocouple placed in position to be heated by said pilotlight and connected in circuit with said electromagnet,

means subject to a condition of said apparatus for openingautomatically, upon the occurrence of such condition, the circuitincluding said thermocouple and said electromagnet to shut oil thesupply of fuel to said main burner when the functioning of the apparatusis such as not to require a supply of fuel to said main burner, meansindependent of said electromagnet and subject to another condition ofthe apparatus other than the heat of thepilot" light on the thermocouplefor automatically resetting said armature to attracted position and saidvalve to open position to establish and maintain a supply of fuel tosaid main burner when the functioning of the apparatus is such as torequire the same, and means under the control of the thermoelectriccurrent generated by the heat of the pilot light on said thermocouplefor disabling, said resetting means upon energization of saidelectromagnet. v

. 11. In a device .of the character described, in combination,a'burner,a fuel supply pipe leading to said burner, a valve in said pipe, asupply pipe for a pilot light in juxtaposition to said burner, anelectromagnet, an armature for said electromagnet which, when attracted,maintains said valve in open position and, when retracted compelsclosing of said valve, a thermocouple placed in position to be heated bysaid pilot light and connected in circuit with said electromagnet, asecond electromagnet connected in circuit with a source of current andadapted for resetting said armature to attracted position, means subjectto the heat supplied by said burner for closing the circuit through saidsecond electromagnet at a predetermined temperature, and a relay in thethermocouple circuit for interrupting the circuit through said secondelectromagnet upon energiaation of said first electromagnet.

12. In a device of the character described, in combination, a burner, afuel supply pipe leading to said burner, a valve in said pipe, a supplypipe for a pilot light in juxtaposition to said burner, anelectromagnet, an armature for said electromagnet which, when attracted,maintains said valve in open position and, when retracted, compelsclosing of said valve, a thermocouple placed in position to be heated bysaid pilot light and connected in circuit with said electromagnet,asecond electromagnet connected in circuit with a source of current andadapted for resetting said armature to attracted position, means subjectto the heat supplied loy said burner for closing the circuit throughsaid second electromagnet at a predetermined temperature, ignition meansfor said pilot light, and a relay in the thermoelectric circuit forinterrupting the circuit through said ignition means and the circuitthrough said second electromagnet upon energization of said firstelectromagnet.

13. In a control device for heating and other apparatus, in combination,a main burner, a fuel supply pipe leading to said burner, a valve insaid pipe, a fuel supply pipe for a pilot light in juxtaposition to saidburner, an electromagnet, an armature for said electromagnet which, whenattracted, maintains said valve in open position and, when retracted,frees said valve for movement to closed position, a thermocouple placed-in position to "be heated by said pilot light and connected in circuitwith said electromagnet,

ill

means subject to a condition of said apparatus for openingautomatically, upon the occurrence oi. such conditiomthe circuitincluding said thermocouple and said electromagnet to shut oil thesupply of fuel to said main" burner when the functioningcf the apparatusis such as not to require a. supply of fuel to said main burner, meansindependent of said electromagnet and subject to another condition ofthe apparatus other than the' heat of the pilot light on thethermocouple for automatically resetting said armature to attractedposition and said valve to open position to establish and maintain asupply of fuel to said main bumerwhen the fimctioning of the apparatusis such as to require thesame, ignition means for said pilot light; andmeans under the control ot'the thermoelectric current generated by theheat of the pilot light on said thermocouple for disabling saidresetting means and said ignition means upon energlzation of saidelectromagnet.

14. In a. control device for heating and other apparatus, incombination, a. main burner, a fuel supply pipe leading to said burner,a valveiin said pipe, 1!. fuel supply p pe for a pil t lichijuxtapositin to said umer, an electromagnet, an armatm'e for saidelectromagnet which, when and, when retracted, frees said valve formovement to closed position, a thermocouple placed in position to beheated by said pilot light and connected in circuit with saidelectromagnet, means subject to a condition of said apparatus foropening automatically, upon the occurrence of such condition, thecircuit including said thermocouple and said electromagnet to shut offthe supply of fuel to said main burner when the functioningof theapparatus isv such as not to require a supply of fuel to said mainburner, and means independent of said electromagnet and subject toanother condition of the apparatus other than the heat of the pilotlight on the thermocouple for automatically resetting said armaturetoattracted position and said valve to open position to establish andmaintain a supply of.

fuel to said main burner when the functioning of the apparatus is suchas to require the same.

15. In a control device for heating and other apparatus, in combination,a main burner, a fuel supply pipe leading to said burner, a valve insaid pipe, a fuel supply pipe for a pilot light in juxtaposition to saidburner, an electromagnet, an armature for said electromagnet which, whenattracted, maintains said valve in open position said secondelectromagnet automatically to reset said armature to attracted positionand said valve to open position to establish and maintain a supply offuel to said main burner when the funcq .tloning of the apparatus issuch as to require the same.

16. In a device of the class described, in combination, heat generatingmeans, means for controlling the supply of operative energy to said heatgenerating means, a pilot light for said heat generating means, athermoelectric generator subject to the heat of said pilot light, anigniter for said pilot light, condition responsive means for renderingsaid igniter operative, and means connected in circuit with saidthermoelectric generator and controlled by the thermoelectric currentgenerated by the heat of the pilot light' onv said thermoelectricgenerator automatically to render said igniter inoperativeupon.energization of said thermoelectric generator.

17. In a device of the class described, in combination, a burner, a fuelsupply pipe leading to said burner, a valvein said pipe, a pilot lightin position to ignite said burner, an electromagattracted, maintainssaid valve in open position net, an armature for said electromagnetwhich, when attracted, maintains said valve in open position and, whenretracted, frees said valve for movement to closed position, athermoelectric enerator placed in position to be heated by said pilot liht and connected in circuit with said electo render said igniterinoperative upon energization of said thermoelectric generator.

18. In a device or the class described, in combination, a burner, athermoelectric generator subject to the heat of said burner, an igniterfor said bumer, condition responsive means for rendering said igniteroperative, and means connected in circuit with said thermoelectricgenerator and controlled by the thermoelectric current generated by theheat of the pilot light on said thermoelectric generator automaticallytorender said igniter inoperative upon energization of said thermoelectricgenerator.

19. In a device of the character described, in combination, a controldvice having an electromagnet provided with an armature connected to acontrolling member and adapted when energized to hold said member inoperating position and when deenergized to release said member to]movement, to a safety position, a second electro magnet adapted forresetting. said armature t attracted position and said controllingmembei to operating position, means responsive to'thi heat of a pilotlight for interrupting the circniiv through said second electromagnetupon completion of the resetting operation, and igniter means connectedin circuit with said second electro-- magnet and disabled by theinterruption of the circuit through said second electromagnet by saidlast mentioned means, said control device controlling the fuel igniterby said igniter.

CHARLES V. HILDEBRECHT.

DISCLAIMER .2,290,048.0haflea Hildebrecht, Chicago, Ill. Sum? DEVICE FORHm'ni'w AND OTHER Armlu'rus. Patent dated July 14, 1942,. Disclaimerfiled July 13, 19:14, by the assigne'e, Milwaukee Gas Specialty Company;the inventor, assentmg, a

Hereby. enter this disclaimer to claims 1, 2, 3, 1'6, and 18 of saidpatent.

[Ofiicial Gazette Augustl', 1944.]

DISCLAIMER v .2,290,048.-0hafles Hildebrecht; Chicago, 111. Sum? DEVICEFOR Hmvmfia AND OTHER APPARATUB. Patent dated July- 14, 1942,.Disclaimer filed July 13, 19:14 by the assigne 'e, -Milwaakee GasSpecialty Company; the inventor, assentmg, v

Hereby. enbefs this disclaimer to claims 1, 2, 3, 1'6, and 18 of saidpatent.

[Oflicial Gazette August'lb', 1944.] a

